Wireless communication apparatus, wireless communication method and wireless communication media

ABSTRACT

A wireless communication apparatus includes a transmitter to transmit a response request signal, a receiver to receives a response transmitted from a wireless communication medium in response to the response request signal, a level detector to detect a response receiving signal level, a memory to store threshold signal level of receiving signal of each type of medium; and a controller to set up a threshold signal level enabling the data writing to a medium to which a response is transmitted based on medium type data included in a response and a threshold signal level of a receiving signal of each type of stored medium, and starts the data writing to a medium to which a response is transmitted when a response receiving signal level is above the threshold signal level.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2003-345819, filed Oct. 3, 2003, the entire contents of all of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wireless communication apparatus for communicating with wireless communication media (wireless IC cards) and a wireless communication method that is applicable to the wireless communication with wireless communication media (wireless IC cards).

2. Description of the Invention

In recent years, from the aspect of safety of data and convenience in carrying, non-contact usable wireless IC cards are in widespread use and various proposals are made relative to the non-contact data or data transmission/receiving such as disclosed in, for example, Japanese Published Patent Application No. 2000-36017.

For example, a wireless IC card is used as a railway ticket. At railway stations, automatic ticket gates are introduced for the purpose of labor saving. So far, an automatic ticket gate receives such magnetic tickets as admission tickets, prepaid cards, commutation tickets, ordinary railway tickets etc. and examines by reading boarding data recorded on the tickets. In recent years, however, it becomes possible for automatic ticket gates to perform the gate processing based on wireless IC cards instead of the above-mentioned magnetic tickets.

However, a wireless IC card is manufactured by many makers and a wireless card reader/writer should be capable of communicating with various wireless IC cards having different communication performances manufactured by various makers.

For example, the communication ranges in which wireless IC cards are able to stably communicate differ for every wireless IC card manufacturing makers. Therefore, it was necessitated to set a communication range wherein wireless card reader/write is enabled to make the communication with IC cards of which the communication ranges are most narrow. Thus, even wireless IC cards having a relatively wide communication range could not receive its benefit.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a wireless communication apparatus capable of making the wireless communication effectively utilizing performances of wireless communication media having different communication performances manufactured by various makers and a wireless communication method. Further, it is also an object to provide a wireless communication medium to which this wireless communication method is applicable.

According to the present invention, there is provided a wireless communication apparatus comprising transmitting means for transmitting a response requesting signal to a wireless communication medium for requesting a response including medium type data showing type of wireless communication media; receiving means for receiving a response transmitted from the wireless communication medium in response to the response requesting signal transmitted by the transmitting means; detecting means for detecting the response receiving signal level; storage means for storing plural threshold signal levels of receiving signals for each type of media correlated with the medium type data showing type of wireless communication media; reading means for reading the threshold signal levels from the storage means based on the medium type data showing type of wireless communication media included in the response received by the receiving means; comparing means for comparing the receiving signal level of the response detected by the detecting means with the threshold signal level that is read by the reading means; and control means for starting the writing of specified data to the wireless communication medium to which the response is transmitted when the receiving signal level is larger than the threshold signal level by the comparing means.

Further, according to the present invention, there is provided a wireless communication method comprising transmitting a response requesting signal to a wireless communication medium for requesting a response including medium type data showing type of wireless communication media; receiving a response transmitted from the wireless communication medium in response to the response requesting signal; detecting the response receiving signal level; storing plural threshold signal levels of receiving signals for each type of media correlated with the medium type data showing type of wireless communication media in a storage means; reading the threshold signal levels from the storage means based on the medium type data showing type of wireless communication media included in the response; comparing the response receiving signal level with the threshold signal level; and starting the writing of specified data to the wireless communication medium to which the response is transmitted when the receiving signal level is larger than the threshold signal level determined by the comparison.

Further, according to the present invention, there is provided a wireless communication medium capable of wireless communication with the wireless communication apparatus, comprising storage means for storing medium type data showing type of this medium; receiving means for receiving a response request signal to request a response transmitted from the wireless communication apparatus; and transmitting means for transmitting a response including the medium type data stored in the storage means to the wireless communication apparatus in response to the response request signal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the schematic construction of a wireless IC card reader/writer (a wireless communication equipment) involved in an embodiment of the present invention;

FIG. 2 is a block diagram showing the schematic construction of a wireless IC card (a wireless communication medium) involved in an embodiment of the present invention;

FIG. 3 is a schematic diagram for explaining a difference between a poling receivable range by a wireless IC card C and a series process receivable range;

FIG. 4 is a timing chart for explaining the wireless communication process between a wireless IC card reader/writer and a wireless IC card;

FIG. 5 is a flowchart for explaining the wireless communication process between a wireless IC card reader/writer and a wireless IC card; and

FIG. 6 is a table showing samples of read/write signals for every wireless IC card makers.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a block diagram showing the schematic construction of a wireless IC card reader/writer (a wireless communication equipment) involved in an embodiment of the present invention. As shown in FIG. 1, a wireless IC card reader/writer 10 is provided with an antenna 11, a transmitter/receiver unit 12, a level detector 13, an A/D converter 14, a controller 15, and a memory 16. Further, transmitter/receiver unit 12 is provided with a transmitter 12 a and a receiver 12 b.

Antenna 11 transmits/receives radio wave to/from a wireless IC card C. Transmitter 12 a modulates signals that are sent to wireless IC card C under the control of controller 15 and supplies modulated signals to antenna 11. Receiver 12 b demodulates signals received through antenna 11 and supplies to controller 15. Level detector 13 detects a signal level of the received signal. For example, level detector 13 detects a signal level of the received signal. The result of detection by level detector 13, for example, a signal level of the received signal is A/D converted by A/D converter 14 and supplied to controller 15.

Memory 16 stores card type data showing type of wireless IC card C and communication performance data showing the communication performance corresponding to card type data. As card type data showing type of wireless IC card, there are, for example, manufacturing maker codes and manufacturing codes. As communication performance data showing communication performance, there is a threshold signal level showing a lower limit of received signal level (a signal level when a signal sent from a wireless IC card was received. That is, memory 16 stores received signal levels that are minimum necessary for every types of wireless IC card C. As shown in the table in FIG. 7, for example, there are A and B Companies as wireless IC card makers. A read signal level of wireless IC card manufacture by A Company is 3V and a wire signal level is 5V. A read signal level of wireless IC card manufactured by B Company is 4V and a write signal level is 6V. A read signal level of wireless IC card manufactured by C Company is 2V and a write signal level is 5V. The table shown in FIG. 7 is stored in memory 16 as the communication performance data showing the communication performance corresponding to card type data.

FIG. 2 is a block diagram showing the schematic construction of a wireless IC card (a wireless communication medium) involved in an embodiment of the present invention. As shown in FIG. 2, wireless IC card C is provided with an antenna 21, a transmitter/receiver 22, a rectifier 23, a battery 24, a controller 25, and a memory 26.

Antenna 21 transmits/receives to/from wireless IC card reader/writer. A transmitter 22 a modulates signals that are transmitted to wireless IC card reader/writer 10 under the control of controller 25 and supplies this modulated transmission signal to antenna 21. A receiver 22 b demodulates the signal received through antenna 21 and supplies this demodulated received signal to controller 25. Rectifier 23 rectifies charging radio wave received through antenna 21 and by converting into electric energy, supplies this electric energy to battery 24. Battery 24 accumulates (charges) the electric energy sent from rectifier 23 and supplies an operating power source to every portions of the card. Memory 26 stores data showing types of this wireless IC cards. As type data showing wireless IC card C, there are manufacturing maker codes and manufacturing codes.

Wireless IC card reader/writer 10 communicates with wireless IC card C according to a communication system called as the polling. First, controller 15 of wireless IC card reader/writer 10 transmits a response requesting signal (polling) requesting a response to wireless IC card C through transmitter 12 a and antenna 11. Wireless IC card C receives the response requesting signal (polling) from wireless IC card reader/writer 10 through antenna 21, generates electric power from this response requesting signal by rectifier 23. The generated power is accumulated in battery 24 and power accumulated in battery 24 is supplied to each unit. Further, wireless IC card C returns a response to wireless IC card reader/writer 10 in response to the received response request signal (polling). In this response, card type data showing type of this wireless IC card C stored in memory 26 of wireless IC card, for example, a name of maker manufactured this wireless IC card is contained. Wireless IC card reader/writer 10 receives a response transmitted from wireless IC card C through antenna 11 and receiver 12 b, confirms a specified wireless IC card C and performs a series of actual data transmission/receiving with the specified wireless IC card C.

What should be noted here is a point that an area capable of the polling receiving by wireless IC card C differs from an area capable of a series process receiving. That is a communication distance enabling generation of electric power by wireless IC card C through the polling communication differs from the communication distance enabling the writing of data onto wireless IC card C, and even when generation of electric power is enabled, data may not be written actually. Further, in the polling receiving enable area, the polling receiving only is possible and actual data writing is not possible. However, it is enabled to actually write data in an area wherein a series process receiving is possible and the polling receiving is also possible.

Further, the polling receivable area and the series process receivable area are non-uniform depending on type of wireless IC card C. For example, in a case of a wireless IC card C of some maker, the polling cannot be received unless the card is brought sufficiently close to an antenna of a wireless IC card reader/writer or in case of another wireless IC card C of another maker, a response cannot be returned sufficiently to the polling unless a wireless IC card C is brought sufficiently to an antenna of a wireless IC card reader/writer or in case of another wireless IC card C of another maker, the polling can be received even when relatively away from an antenna of a wireless IC card C or in case of another wireless IC card C of another maker, a response can be returned to the polling even when relatively away from an antenna of a wireless IC card reader/writer.

Further, in case of a wireless IC card C of some maker, data can not be written unless the card is brought sufficiently close to an antenna of a wireless IC card reader/writer and electric power of about 5V power is generated from the received signal and in case of a wireless IC card C of another maker, data can be written when the card is relatively away from an antenna of a wireless IC card reader/writer and electric power of about 3V is generated.

As described above, the transmission capacity and receiving capacity differ according to type of wireless. IC card C and the communication range (electric power demanded for writing) wherein wireless IC card C is enabled to communicate stably differ for each wireless IC card manufacturer. Therefore, it is necessary for wireless IC card reader/writer to set a communication range to enable the communication with wireless IC card C of the most narrow communication range (wireless IC card C demanding large electric power in the data writing). However, as a result, even wireless IC card having a relatively wide communication range (wireless IC card demanding small electric power in the data writing) will lose its benefit.

So, in the present invention, memory 16 of wireless IC card reader/writer 10 stores card type data showing type of wireless IC card C and communication performance data showing communication performance corresponding to card type data. And based on card type data contained in a response from wireless IC card C, the communication performance of this wireless IC card is determined and a communication range corresponding to the communication performance of this wireless IC card C is set. Thus, the optimum communication corresponding to the communication performance of this wireless IC card C is enabled.

That is, as shown in the table in FIG. 6, as card type data contained in a response from wireless IC card C, a voltage value needed to read/write corresponding to a manufacture name of that card is stored in memory 16 of wireless IC card reader/writer 190. Thus, when a communication range corresponding to the communication performance of wireless IC card C is set by wireless IC card reader/writer 10, the optimum communication corresponding the communication performance of this wireless IC card C is enabled.

Next, the wireless communication with wireless IC card reader/writer and wireless IC card C described above; in other words, the communication control by type of card; that is, according to the communication performance corresponding to a manufacturer of wireless IC card C will be explained referring to a flowchart shown in FIG. 4 and a timing chart shown in FIG. 5.

As shown in FIG. 4 and FIG. 5, for communication with wireless IC card C through transmitter 12 a and antenna 11, wireless IC card reader/writer 10 transmits a response requesting signal (polling) to request a response, repeatedly (ST1). When a response signal (polling) transmitted from wireless IC card reader/writer 10 through antenna 21 and receiver 22 b, wireless IC card C returns a response containing a manufacturer code indicating a maker f the wireless IC card C as card type data showing own card type.

When a response transmitted from wireless IC card C through antenna 11 and receiver 12 b (ST2, YES), wireless IC card reader/writer detects a receiving signal level S1 of the response received by level detector 13 (ST3). At the same time, controller 15 recognizes card type data contained in the received response (ST4). Then, reading out card type data stored in memory 16; that is, a threshold signal level correlated with each card maker, sets a threshold signal level S2 that is capable of writing data to wireless IC card transmitting a response based on this threshold signal level (ST5).

For example, when a maker name of wireless IC card C is A Company, a signal level required for its reading is 3V and a signal level required for the writing is 5V as shown in the table shown in FIG. 6. Therefore, a threshold signal level S2 corresponding to these values is set.

When a maker name of wireless IC card C is B company, a signal level required for its reading is 4V and a signal level required for the writing is 6V and a threshold signal level S2 is set corresponding to these values.

When a maker name of wireless IC card C is C Company, a signal level required for its reading is 2V, and a signal level required for the writing is 5V, and a threshold signal level S2 is set.

Further, controller 15 compares the set threshold signal level S2 with the receiving signal level S1 of a response from actual wireless IC card C (ST6). When the receiving signal level S1 of the response from wireless IC card C is less than the threshold signal level S2 (ST6, NO) as a result of the comparison, a response requesting signal (polling) is transmitted without shifting to the actual process (data writing, etc.) (ST1) and waiting until the receiving signal level of a received response (ST2) becomes above the threshold signal level (ST6, YES), the actual processing is started. When the receiving signal level S1 of the response from wireless IC card C is above the threshold signal level S2 as a result of the comparison (ST6, YES), the actual processing is started. That is, the data writing, etc. to wireless IC card C is started (ST7).

As explained above, according to the present invention, when wireless IC card is brought to a distance close to wireless IC card reader/writer so that actual process such as data writing, etc. can be made stably, the writing is started and therefore, it becomes possible to stabilize the communication. Further, even when a distance to make the writing varies depending on card maker, card model number, etc., a threshold signal level is decided based on card type data retained in wireless IC card and the actual process is started by checking whether this threshold signal level is cleared. Therefore, the communication at a communication distance suited to every card becomes possible. Further, it is possible to know the behavior of wireless IC card as to whether it is closing to or getting away from wireless IC card reader/writer by monitoring the receiving level of the signal transmitted from wireless IC card. Therefore, when wireless IC card is away from wireless IC card reader/writer, it is possible to stabilize the communication through such actions as interruption of the communication.

Further, the present invention is not limited to the embodiment described above but can be modified variously within the scope departing from the spirit and scope thereof in the embodiments. Further, the embodiments described above may be combined as appropriate to the extent possible and in this case, combined effects are obtained. Further, inventions at various states are included in the above-mentioned embodiments and various inventions are derived through combination of disclosed plural component elements. For example, even when some of components elements are deleted from whole component elements shown in the embodiments, the problems presented for solution by the invention can be solved and effects described in the effects of the invention are obtained, the construction with the component elements deleted can be derived as an invention.

According to the present invention, it is possible to provide a wireless communication apparatus capable of making the wireless communication effectively utilizing the performance of wireless communication media in difference communication performance manufacture by various makers and a wireless communication method. Further, wireless communication media to which this communication method is applicable can be provided. 

1. A wireless communication apparatus for wireless communication with wireless communication media, comprising: transmitting means for transmitting a response requesting signal to a wireless communication medium; receiving means for receiving a response transmitted from the wireless communication medium in response to the response requesting signal transmitted by the transmitting means, the response including medium type data showing type of wireless communication media; detecting means for detecting a signal level of the response; storage means for storing plural threshold signal levels of receiving signals for each type of media correlated with the medium type data showing type of wireless communication media; reading means for reading the threshold signal level from the storage means based on the medium type data included in the response received by the receiving means; comparing means for comparing the signal level of the response detected by the detecting means with the threshold signal level read by the reading means; and control means for starting the writing of specified data to the wireless communication medium to which the response is transmitted when the receiving signal level is larger than the threshold signal level by the comparing means.
 2. The wireless communication apparatus as set force in claim 1, wherein the control means transmits the response request signal again by the transmitting means without starting the writing the specified data to the wireless communication medium when the response received signal level is below the threshold signal level compared by the comparing means, and starts the writing of the specified data to the wireless communication medium to which the response is transmitted when the received signal level received again by the receiving is determined to be larger than the threshold signal level by the comparing means.
 3. The wireless communication apparatus as set force in claim 1, wherein the medium type data includes a name of maker who produced wireless communication media.
 4. A wireless communication method applicable to the wireless communication with wireless communication media comprising: transmitting a response requesting signal to a wireless communication medium for requesting a response including medium type data showing type of wireless communication media; receiving a response transmitted from the wireless communication medium in response to the response requesting signal; detecting the response receiving signal level; storing plural threshold signal levels of receiving signals for each type of media correlated with the medium type data showing type of wireless communication media in a storage means; reading the threshold signal levels from the storage means based on the medium type data showing type of wireless communication media included in the response; comparing the response receiving signal level with the threshold signal level; and starting the writing of specified data to the wireless communication medium to which the response is transmitted when the receiving signal level is larger than the threshold signal level determined by the comparison.
 5. The wireless communication method as set force in claim 4, wherein when the response receiving signal level is decided to be smaller than the threshold signal level by the comparison in the comparing step, the writing process is not started but the response request signal is transmitted again and when the receiving signal level of the response received again is decided to be larger than the threshold signal level in the comparing step, specified data writing to the wireless communication medium to which the response is transmitted is started.
 6. A wireless communication medium capable of wireless communication with the wireless communication apparatus, comprising: storage means for storing medium type data showing type of this medium; receiving means for receiving a response request signal to request a response transmitted from the wireless communication apparatus; and transmitting means for transmitting a response including the medium type data stored in the storage means to the wireless communication apparatus in response to the response request signal.
 7. The wireless communication medium as set force in claim 6, wherein the medium type data includes a name of maker who manufactured wireless communication media. 